Vulcanization of rubber



Patented Jan. 5, 1925. I I

HERBERT SKELLON, OF MIDDLETON, ENGLAND. ASSIGNOB OF TWO-THIR'DS T T0193HARTLEY ROBERTS, QF SURREY, ENGLAND, AND HUBE-BT BRYAN RANKIN CLARKE, 0FR A DLETT HERTS, ENGLAND.-

VULCANiZA-IION or Bil BEER.

No Drawing.

' To all whom it may concern:

Be it known that I, HERBERT Station, a subject of the King of GreatBritain and Ireland, and resident of Middleton, in the 6 .county ofLancaster, England, have invented certain new and'useful ImprovementsRelating -.to the vulcanization of Rubber, 01 which thefollowing is aspecification.

v This invention has for its-object to pro- 10 vide for the more ra idcuring or vulcanization of rubber .wit outin an material way affectingtheproperti'es of t e finished product. I I I The invention comprisesthe incorportt tion with the rubber mixingprior to curing or heattreatment of a material tormed by. the reaction of anhydrous zincsulphate with ammonia with the addition, if not already present in themixing,'of .free zinc oxide.

In one convenientapplication of my in vention, I'incorporate with therubbermixing prior to curing 'or heat treatment from 1% upwards (of theweight of rubber in the mixing of 26 (Zn'.SO,5 w liCh is adouble comound formed between anhydrous zinc su phate and dry ammonia wlth anapproximately.

equalpercentage of zinc oxide. In the subsequent curing operation, thesaid mixture 30 of compounds accelerates the vulcanizing process withoutmaterially affecting the product obtained. Some of the basic zincsulphates contain/ a high percentage of zinc oxide and can be enta-aminozinc sulphate.

Application filed March 26, 1923. Serial No. 627,879.

used without any further addition of zinc oxide to the mixture."

As an example of a suitable mixingz- An ordinary rubber mixingcontaining 48% rubber, 49% fillers and3% sulphur would be cured in about90 minutes at lbs. steam 40 pressure. If, however, from 1% to 2% (of theweight of rubber in the mixing) of ertual proportions of penta-aminozinc sulp ate and z'no oxide be added to the'mixing, the time of cure isreduced to about 20 min 5 utes.

I do not limit myself to any particular rubber mixing or proportion ofaccelerator but may vary the same'to suit requirements.

1. In the vulcanization of rubber, the incorporation with the rubbermixing prior to curing or heat treatment. of a material formed by thereaction of anhydrous zine sulphate with ammonia, with the addition, ifnot already present in the mixing, of free zinc oxide, as set forth.

2. As an accelerator in the vulcanization of indie-rubber, amateria'lformed by the reaction of anhydrous zinc sulphate with ammonia, as setforth.

3. As an accelerator in the vulcanization of indie-rubber, a materialformed of equal proportions by weight of penta-amino zincand zincoxide,oas set forth 1 7 In testimony'whereof I have signed my name tothis specification.

HERBERT SKELLON.

